(1) Field of the Invention
This invention generally relates to a multiline tow cable assembly including a swivel and slip ring. More particularly, the invention relates to a multiline array assembly including a swivel and slip ring combination for use between a tow cable and a towed array.
(2) Description of the Prior Art
The following patents, for example, disclose towing and mooring of vessels using rings, and in some instances swivel type rings, but do not disclose a swivel and slip ring assembly for reducing the torque on a towed object.
Specifically, U.S. Pat. No. 3,167,103 to Hawthorne et al. relates to flexible vessels such as barges and storage containers, particularly collapsible vessels intended primarily for the transport and/or storage of fluids and pourable solids. The device more particularly focuses on improving the method of manufacture of the vessel. According to the disclosure, a flexible envelope for a vessel is attached to a retaining ring which is adapted to be secured to a rigid end piece of the vessel, the end piece being provided with an annular shoulder against which the ring bears when the envelope is taut. The envelope may be attached to the ring by having its strength-giving layer turned over the ring and then sewn to itself. The shoulder may be formed by a recessed emplacement for the ring provided in the end piece or by one of two annular plates for which a seating is provided on the end-piece and between which the ring can be clamped.
U.S. Pat. No. 3,670,686 to Reynolds discloses a submerged mooring system for a tanker which is being loaded or unloaded. The mooring system permits the tanker to drift with the wind and/or current while maintaining the bow of the tanker headed toward the anchor point. The mooring system incorporates a swivel which rotates around a vertical axis as the heading of the tanker changes with variations in the wind and/or current. The swivel comprises a column means, a circular mooring ring loosely encircling and slidable circumferentially around the column means, means for retaining the mooring ring on the column means, and a slip ring linked with and slidable circumferentially of the mooring ring, the mooring line being connected to the slip ring. A hose for loading or unloading the tanker extends between the tanker and the mooring system and the mooring system incorporates another swivel which permits the hose to swivel about the same axis as the mooring swivel in response to changes in the heading of the tanker.
U.S. Pat. No. 3,793,623 to Gongwer discloses a hydrodynamic stabilizing device for use in high speed deployment and recovery of cable-suspended underwater devices making use of a swivelable tail or shroud. The device shown is a generally cylindrical underwater sonar transducer having a comparatively flat or blunt frontal surface entering the water and a tapered configuration near the upper or cable-suspended end and having a spaced frustoconical shroud or tail structure. The means of attachment of the cable to the body of the transducer includes a connector supporting the shroud and having a swivelable joint. A spring in the body is calibrated to hold the connector tightly against the body during descent, thereby holding the shroud firmly in place; but this spring yields under the greater force required to draw the transducer up out of the water, permitting an axial displacement of the connector and releasing the tail or shroud to permit the body to swivel relative to the shroud. Since the shroud always maintains its alignment relative to the end of the cable, perturbations affecting the body will always be damped out, causing the body to trail the shroud and cable, and ascent is as smooth and fast as the descent.
U.S. Pat. No. 4,281,402 to Kruka et al. disclose a marine cable decoupler apparatus for isolating a towed marine streamer from noise transmitted from the tow vessel. The decoupling device comprises a fluid spring positioned in the tow cable with changes in the spring constant being minimized by controlling the fluid pressure.
U.S. Pat. No. 4,756,268 to Gjestrum et al. disclose an angular member provided on seismic cables towed by a vessel and laterally displaced in parallel and in relation to the course of the vessel. The angular member comprises a frame at least partly enclosing the cable in the area of angular deflection between an inner cable portion and extending obliquely to the towing direction and the active main cable portion. The frame is formed of two frame plates secured in a spaced relationship and having at the lead-in end for the cable a cable-fastening device and at the other end a pivotable ramp swingable in the plane of the frame plates. The ramp has a further fastening device for the cable. Another fastening device is pivotably connected to the frame plates for connecting thereto a wire to a paravane or the like. When towed in the water the angular member absorbs most of the forces normally exerted on the cable at the area of angular deflection.
It should be understood that the present invention would in fact enhance the functionality of the above patents by providing a continuous electrical connection between a tow cable and towed array without damaging electrical components due to torque on the assembly. The enhanced functionality of the present invention is achieved at least in part by providing a combined swivel and slip ring assembly at an aft end of the tow cable.